This invention relates to shift actuator in a shift mechanism of a geared transmission capable of shifting to overdrive automatically.
Geared manual transmissions have long come equipped with an overdrive shift mechanism. In a transmission with five forward speeds, for example, fifth speed is overdrive. Overdrive enables fuel consumption to be improved by making the gear ratio less than one at high traveling speeds.
In a manual transmission, however, the state of the art is such that overdrive involves a complicated shifting operation and therefore is used only infrequently. Though use of overdrive in, say, a long distance truck can result in a considerable fuel savings, overdrive is not utilized very often for the abovementioned reason. In order to foster the use of overdrive, a geared transmission in which only the shift to overdrive is automated has been developed, as set forth in the specification of U.S. Pat. No. 2,548,761.